From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001

From: Peter Jones <pjones@redhat.com>

Date: Wed, 16 Jan 2019 13:21:46 -0500

Subject: [PATCH] Add efi-export-env and efi-load-env commands

This adds "efi-export-env VARIABLE" and "efi-load-env", which manipulate the

environment block stored in the EFI variable

GRUB_ENV-91376aff-cba6-42be-949d-06fde81128e8.

Signed-off-by: Peter Jones <pjones@redhat.com>

---

 grub-core/Makefile.core.def  |   6 ++

 grub-core/commands/efi/env.c | 168 +++++++++++++++++++++++++++++++++++++++++++

 grub-core/kern/efi/efi.c     |   3 +

 grub-core/kern/efi/init.c    |   5 --

 grub-core/lib/envblk.c       |  43 +++++++++++

 util/grub-set-bootflag.c     |   1 +

 include/grub/efi/efi.h       |   5 ++

 include/grub/lib/envblk.h    |   3 +

 8 files changed, 229 insertions(+), 5 deletions(-)

 create mode 100644 grub-core/commands/efi/env.c

diff --git a/grub-core/Makefile.core.def b/grub-core/Makefile.core.def

index 1e15345107e..81fc274148e 100644

--- a/grub-core/Makefile.core.def

+++ b/grub-core/Makefile.core.def

@@ -820,6 +820,12 @@ module = {

   enable = efi;

 };

+module = {

+  name = efienv;

+  common = commands/efi/env.c;

+  enable = efi;

+};

+

 module = {

   name = efifwsetup;

   efi = commands/efi/efifwsetup.c;

diff --git a/grub-core/commands/efi/env.c b/grub-core/commands/efi/env.c

new file mode 100644

index 00000000000..cbd13e03e81

--- /dev/null

+++ b/grub-core/commands/efi/env.c

@@ -0,0 +1,168 @@

+/*

+ *  GRUB  --  GRand Unified Bootloader

+ *  Copyright (C) 2012  Free Software Foundation, Inc.

+ *

+ *  GRUB is free software: you can redistribute it and/or modify

+ *  it under the terms of the GNU General Public License as published by

+ *  the Free Software Foundation, either version 3 of the License, or

+ *  (at your option) any later version.

+ *

+ *  GRUB is distributed in the hope that it will be useful,

+ *  but WITHOUT ANY WARRANTY; without even the implied warranty of

+ *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the

+ *  GNU General Public License for more details.

+ *

+ *  You should have received a copy of the GNU General Public License

+ *  along with GRUB.  If not, see <http://www.gnu.org/licenses/>.

+ */

+#include <grub/dl.h>

+#include <grub/mm.h>

+#include <grub/misc.h>

+#include <grub/types.h>

+#include <grub/mm.h>

+#include <grub/misc.h>

+#include <grub/efi/api.h>

+#include <grub/efi/efi.h>

+#include <grub/env.h>

+#include <grub/lib/envblk.h>

+#include <grub/command.h>

+

+GRUB_MOD_LICENSE ("GPLv3+");

+

+static const grub_efi_guid_t grub_env_guid = GRUB_EFI_GRUB_VARIABLE_GUID;

+

+static grub_err_t

+grub_efi_export_env(grub_command_t cmd __attribute__ ((unused)),

+                    int argc, char *argv[])

+{

+  const char *value;

+  char *old_value;

+  struct grub_envblk envblk_s = { NULL, 0 };

+  grub_envblk_t envblk = &envblk_s;

+  grub_err_t err;

+  int changed = 1;

+  grub_efi_status_t status;

+

+  grub_dprintf ("efienv", "argc:%d\n", argc);

+  for (int i = 0; i < argc; i++)

+    grub_dprintf ("efienv", "argv[%d]: %s\n", i, argv[i]);

+

+  if (argc != 1)

+    return grub_error (GRUB_ERR_BAD_ARGUMENT, N_("variable name expected"));

+

+  grub_efi_get_variable ("GRUB_ENV", &grub_env_guid, &envblk_s.size,

+                         (void **) &envblk_s.buf);

+  if (!envblk_s.buf || envblk_s.size < 1)

+    {

+      char *buf = grub_malloc (1025);

+      if (!buf)

+        return grub_errno;

+

+      grub_memcpy (buf, GRUB_ENVBLK_SIGNATURE, sizeof (GRUB_ENVBLK_SIGNATURE) - 1);

+      grub_memset (buf + sizeof (GRUB_ENVBLK_SIGNATURE) - 1, '#',

+	      DEFAULT_ENVBLK_SIZE - sizeof (GRUB_ENVBLK_SIGNATURE) + 1);

+      buf[1024] = '\0';

+

+      envblk_s.buf = buf;

+      envblk_s.size = 1024;

+    }

+  else

+    {

+      char *buf = grub_realloc (envblk_s.buf, envblk_s.size + 1);

+      if (!buf)

+	return grub_errno;

+

+      envblk_s.buf = buf;

+      envblk_s.buf[envblk_s.size] = '\0';

+    }

+

+  err = grub_envblk_get(envblk, argv[0], &old_value);

+  if (err != GRUB_ERR_NONE)

+    {

+      grub_dprintf ("efienv", "grub_envblk_get returned %d\n", err);

+      return err;

+    }

+

+  value = grub_env_get(argv[0]);

+  if ((!value && !old_value) ||

+      (value && old_value && !grub_strcmp(old_value, value)))

+    changed = 0;

+

+  if (old_value)

+    grub_free(old_value);

+

+  if (changed == 0)

+    {

+      grub_dprintf ("efienv", "No changes necessary\n");

+      return 0;

+    }

+

+  if (value)

+    {

+      grub_dprintf ("efienv", "setting \"%s\" to \"%s\"\n", argv[0], value);

+      grub_envblk_set(envblk, argv[0], value);

+    }

+  else

+    {

+      grub_dprintf ("efienv", "deleting \"%s\" from envblk\n", argv[0]);

+      grub_envblk_delete(envblk, argv[0]);

+    }

+

+  grub_dprintf ("efienv", "envblk is %lu bytes:\n\"%s\"\n", envblk_s.size, envblk_s.buf);

+

+  grub_dprintf ("efienv", "removing GRUB_ENV\n");

+  status = grub_efi_set_variable ("GRUB_ENV", &grub_env_guid, NULL, 0);

+  if (status != GRUB_EFI_SUCCESS)

+    grub_dprintf ("efienv", "removal returned %ld\n", status);

+

+  grub_dprintf ("efienv", "setting GRUB_ENV\n");

+  status = grub_efi_set_variable ("GRUB_ENV", &grub_env_guid,

+				  envblk_s.buf, envblk_s.size);

+  if (status != GRUB_EFI_SUCCESS)

+    grub_dprintf ("efienv", "setting GRUB_ENV returned %ld\n", status);

+

+  return 0;

+}

+

+static int

+set_var (const char *name, const char *value,

+	 void *whitelist __attribute__((__unused__)))

+{

+  grub_env_set (name, value);

+  return 0;

+}

+

+static grub_err_t

+grub_efi_load_env(grub_command_t cmd __attribute__ ((unused)),

+                    int argc, char *argv[] __attribute__((__unused__)))

+{

+  struct grub_envblk envblk_s = { NULL, 0 };

+  grub_envblk_t envblk = &envblk_s;

+

+  grub_efi_get_variable ("GRUB_ENV", &grub_env_guid, &envblk_s.size,

+                         (void **) &envblk_s.buf);

+  if (!envblk_s.buf || envblk_s.size < 1)

+    return 0;

+

+  if (argc > 0)

+    return grub_error (GRUB_ERR_BAD_ARGUMENT, N_("unexpected argument"));

+

+  grub_envblk_iterate (envblk, NULL, set_var);

+  grub_free (envblk_s.buf);

+}

+

+static grub_command_t export_cmd, loadenv_cmd;

+

+GRUB_MOD_INIT(lsefi)

+{

+  export_cmd = grub_register_command ("efi-export-env", grub_efi_export_env,

+	    N_("VARIABLE_NAME"), N_("Export environment variable to UEFI."));

+  loadenv_cmd = grub_register_command ("efi-load-env", grub_efi_load_env,

+	    NULL, N_("Load the grub environment from UEFI."));

+}

+

+GRUB_MOD_FINI(lsefi)

+{

+  grub_unregister_command (export_cmd);

+  grub_unregister_command (loadenv_cmd);

+}

diff --git a/grub-core/kern/efi/efi.c b/grub-core/kern/efi/efi.c

index 2a446f5031b..14bc10eb564 100644

--- a/grub-core/kern/efi/efi.c

+++ b/grub-core/kern/efi/efi.c

@@ -225,6 +225,9 @@ grub_efi_set_variable(const char *var, const grub_efi_guid_t *guid,

   if (status == GRUB_EFI_SUCCESS)

     return GRUB_ERR_NONE;

+  if (status == GRUB_EFI_NOT_FOUND && datasize == 0)

+    return GRUB_ERR_NONE;

+

   return grub_error (GRUB_ERR_IO, "could not set EFI variable `%s'", var);

 }

diff --git a/grub-core/kern/efi/init.c b/grub-core/kern/efi/init.c

index 2d12e6188fd..0574d8d6217 100644

--- a/grub-core/kern/efi/init.c

+++ b/grub-core/kern/efi/init.c

@@ -85,11 +85,6 @@ stack_protector_init (void)

 grub_addr_t grub_modbase;

-#define GRUB_EFI_GRUB_VARIABLE_GUID \

-  { 0x91376aff, 0xcba6, 0x42be, \

-    { 0x94, 0x9d, 0x06, 0xfd, 0xe8, 0x11, 0x28, 0xe8 } \

-  }

-

 /* Helper for grub_efi_env_init */

 static int

 set_var (const char *name, const char *value,

diff --git a/grub-core/lib/envblk.c b/grub-core/lib/envblk.c

index 2e4e78b132d..874506da169 100644

--- a/grub-core/lib/envblk.c

+++ b/grub-core/lib/envblk.c

@@ -223,6 +223,49 @@ grub_envblk_delete (grub_envblk_t envblk, const char *name)

     }

 }

+struct get_var_state {

+  const char * const name;

+  char * value;

+  int found;

+};

+

+static int

+get_var (const char * const name, const char * const value, void *statep)

+{

+  struct get_var_state *state = (struct get_var_state *)statep;

+

+  if (!grub_strcmp(state->name, name))

+    {

+      state->found = 1;

+      state->value = grub_strdup(value);

+      if (!state->value)

+	grub_errno = grub_error (GRUB_ERR_OUT_OF_MEMORY, N_("out of memory"));

+

+      return 1;

+    }

+

+  return 0;

+}

+

+grub_err_t

+grub_envblk_get (grub_envblk_t envblk, const char * const name, char ** const value)

+{

+  struct get_var_state state = {

+      .name = name,

+      .value = NULL,

+      .found = 0,

+  };

+

+  grub_envblk_iterate(envblk, (void *)&state, get_var);

+

+  *value = state.value;

+

+  if (state.found && !state.value)

+    return grub_errno;

+

+  return GRUB_ERR_NONE;

+}

+

 void

 grub_envblk_iterate (grub_envblk_t envblk,

                      void *hook_data,

diff --git a/util/grub-set-bootflag.c b/util/grub-set-bootflag.c

index bb198f02351..6a79ee67444 100644

--- a/util/grub-set-bootflag.c

+++ b/util/grub-set-bootflag.c

@@ -25,6 +25,7 @@

 #include <config-util.h>     /* For *_DIR_NAME defines */

 #include <grub/types.h>

+#include <grub/err.h>

 #include <grub/lib/envblk.h> /* For GRUB_ENVBLK_DEFCFG define */

 #include <errno.h>

 #include <stdio.h>

diff --git a/include/grub/efi/efi.h b/include/grub/efi/efi.h

index 2e0691454b1..8dfc89a33b9 100644

--- a/include/grub/efi/efi.h

+++ b/include/grub/efi/efi.h

@@ -24,6 +24,11 @@

 #include <grub/dl.h>

 #include <grub/efi/api.h>

+#define GRUB_EFI_GRUB_VARIABLE_GUID \

+  { 0x91376aff, 0xcba6, 0x42be, \

+    { 0x94, 0x9d, 0x06, 0xfd, 0xe8, 0x11, 0x28, 0xe8 } \

+  }

+

 /* Variables.  */

 extern grub_efi_system_table_t *EXPORT_VAR(grub_efi_system_table);

 extern grub_efi_handle_t EXPORT_VAR(grub_efi_image_handle);

diff --git a/include/grub/lib/envblk.h b/include/grub/lib/envblk.h

index c3e65592170..ab969af2461 100644

--- a/include/grub/lib/envblk.h

+++ b/include/grub/lib/envblk.h

@@ -22,6 +22,8 @@

 #define GRUB_ENVBLK_SIGNATURE	"# GRUB Environment Block\n"

 #define GRUB_ENVBLK_DEFCFG	"grubenv"

+#define DEFAULT_ENVBLK_SIZE	1024

+

 #ifndef ASM_FILE

 struct grub_envblk

@@ -33,6 +35,7 @@ typedef struct grub_envblk *grub_envblk_t;

 grub_envblk_t grub_envblk_open (char *buf, grub_size_t size);

 int grub_envblk_set (grub_envblk_t envblk, const char *name, const char *value);

+grub_err_t grub_envblk_get (grub_envblk_t envblk, const char * const name, char ** const value);

 void grub_envblk_delete (grub_envblk_t envblk, const char *name);

 void grub_envblk_iterate (grub_envblk_t envblk,

                           void *hook_data,